Dr. Johns is an aquatic scientist who specializes in aquatic ecological risk assessments (ERAs), particularly those associated with contaminated sediment. The focus of his 30 years of professional experience has been on the effects of toxic pollutants on aquatic organisms. Dr. Johns is responsible for the management of large, multi-task, multi-disciplinary environmental investigations, including remedial investigation/feasibility studies (RI/FSs) and natural resource damage assessments (NRDAs).